Method and apparatus for burning cement



Feb. 21, 1933. R. w. P. HORN ET AL METHOD AND APPARATUS FOR BURNINGCEMENT 2 Sheets-Sheet 1 Filed Sept. 22, 1927 Feb. 21, 1933. R w p N ETAL 1,898,776

METHOD AND APPARATUS FOR BURNING bEMENT Filed Sept. 22, 1927 2Sheets-Sheet 2 Patented Feb. 21, 1933 Uilllfil) STATES T ROBERT W. P.I-ZORN, OF ALLENTOVN, AN'D JACOB H..NISSLEY, 0F MANHEIM, PENNSYLVANIAMETHOD AND APPABATUS'FOR BURNING- CEMENT Application filed September 221927. Serial No. 221,332.

This invention relates to a method and apparatus for burning cement orsimilar materials. As heretofore generally practiced, cement is usuallyburned in an inclined rotary kiln open to the atmosphere, the necessaryclinkering temperature being maintained by injecting fuel into the endof the kiln opposite to that which is in communication with the usualstack. This arrangement is highly inefiicient in practice, becauseincomplete combustion takes place in the kiln due to the fact thatexcess air enters the kiln and interferes with complete combustion.Moreover, so far as known, no successful effort has heretofore been madeto utilize the heat in the clinker before its discharge from the kiln,the general practice being to simply dump the red hot clinker from thekiln.

The primary object of this invention is to provide a method of operatinga kiln so that great economies in the consumption of fuel may beobtained. To this end, means are provided to absolutely control thequantity of air, as well as fuel, that enters the kiln, and to sodistribute the air as to secure substantially complete combustion withinthe kiln.

A- further object of the invention is to utilize the heat in the clinkerto substantially raise the temperature of the air that is admitted tothe kiln.

A further object of the invention is to provide a rotary kiln embodyingmeans to discharge the clinker without admitting substantial quantitiesof air to interfere with the control of the air supply to the kiln.

A further object of the invention is to provide a kiln, in which fuel issupplied intermediate the ends thereof, that includes means to retardthe movement of the material longitudinally of the kiln at the point atwhich the fuel is admitted.

A still further object of the invention is to provide a kiln includingmeans to con trol the supply ofair to the interior of the kiln and inwhich a part of the air is utilized to retard the escape of finelydivided solid particles with the gaseous products of combustion throughthe stack.

Still further objects of the invention will appear as a descriptionthereof proceeds with reference to the accompanying drawings, in which,V

.Figure 1 is a side elevation of the im proved kiln.

Figure 2 is a longitudinal section of the feed end of the kiln. I

Figure 3.is a longitudinal section of the converging portion of thekiln. Figure l is a longitudinal section of the discharge end of thekiln.

Figure 5 is a transverse sectiontaken on the plane indicated by the line55 of Figure 3.

Figure 6 is a transverse section taken on the line 66'of,Figure 3.

Figure 7 is a transverse section on theline 77 of Figure l on a reducedscale.

Figure 8 is a transverse section taken on 79 the p lane indicated by theline 88 on Figure 4. Similar reference characters indicate like partsthroughout the several figures.

In the drawings, 1 indicates the rotary 7 kiln as a whole. As clearlyshownin Fig. 1, said kiln comprises a main section 2 and a coolingsection 3 connected together by a throat section 4 of reduced diameteras compared to said main and cooling sections. 80 Section 3 is providedwith a tubular extension 5 for a purposeepresently to be described.Portions 2, 3, 4 and 5 are secured I I together to rotate as a unit. Thekiln is provided with tires 6 that extend peripheral- 35 lytherearoundat intervals throughout the length thereof It is supported for rotationon rollers 7 carried by foundations 8 of any approved type; 'A girthgear9 surrounds section 2, said gear being arranged to mesh with a suitablysupported driving pinion 9 to rotate the kiln. 1 in well known manner.

One cndfof main section 2 extends into a suitable brick housing 10 theinterior of which is in communication with a stack 11. A feed conduit 12having ahopper 13 at one end extends through said housing 10 into themain section 2 of the kiln. Said conduit may be provided with a spiralconthroat section a is veyer of well known form to provide an even feedof raw material to the kiln in well known manner, if desired.

The main section of the kiln adja cent n16 provided with a wall ofincreasing thickness from adjacent the midportion of said sectioncontinuing to the throat section. Preferably, such varying thickness isobtained by a plurality of steps 14. In order that the flow of thematerial through the kiln may not be interrupted to an objectionabledegree, adjacent steps are 17 to prevent the clogging of the material insaid ports. Preferably, but not necessarily, four ports are provided,arranged in pairs at diametrically opposite portions of the kiln but instaggered relation endwise of the kiln as clearly shown in Figure 3.

Extension is divided by walls 18 and 18' to form two chambers 19 and.20. A tube 21 is secured to the outer wall of chamber and extendsaxially of the kiln. A plate 22 closes the end of tube 21, said platebeing provided with a glass peep-hole 23. Spaced from plate 22 are apair of concentrically arranged spacing rings 2a and 25 separating tubes26 and 27 that are arranged within tube 21 and concentrically therewith.Tube 27 opens into the chamber 19 as'clearly shown in Fig. at. Tube 26extends into the end of cooler sect-ion 3 and is provided with a nozzle28 having a plurality of-openings 29 arranged to direct air at asubstantial angle to the axis of the kiln.

Section 5 and tube 21 rotate as a unit with the kiln, a tire 30 beingprovided adjacent the end of said tube. Said tire rests on a pair ofrollers 31 supported by a foundation 32 in well known manner.

Surrounding tube 21 is a stationary casing 33 relative to which the tube21 rotates. In order to reduce the friction between said tube and saidcasing, roller bearings 34 and 35 are provided between the ends of saidcasing and a brass wearing shell 36 that surrounds tube 21. As shown inFig. 4, the outer wall of casing 33 is spaced from shell 36 providing anannular space between said shell and easing. Suitable packing glands 37and 38 bear against shoulders 39 and 40 and are clamped there-acainst byrings 11 and 42 that may be adjusted by bolts 43 threaded in the endwalls of said casing 33 and engaging said rings at intervals.

The annular space between packing 37 and 38 is divided midway betweenits ends by a series of loose annular sealing plates 44 arranged ingrooves 45 of casing 33 and in grooves provided by sleeves 16 secured toshell 36 in any known way. connected to a suitable source of low airpressure combined with fluid or finely divided fuel of any form, suchoil or powdered coal, for example. Ports 48 formed in tube 21 and shell36 putthe annular space to which the pipe 47 is connected incommunication with the annular space between tubes 27 and 21 adjacentthe rear ends of said tubes, ring l9 being provided to divide said spaceinto two sections. Suitable openings 50 are pr vided in tube 27 wherebythe fuel under pressure is permitted to enter the annular soace betweentube26 and 27 and to flow therethrongh to chamber 19.

A pipe 51 c nnected to any suitable source of continuous or pulsatingair under pressure is connected to theannular space forwardly of rings44. Ports 52 place this space in communication with the annular spacebetween tube 21 and 27 forwardly of ring 49. Air under pressure is thussupplied to the chamber 20. I I

From chamber 20 air under pressure is conveyed lengthwise ofthe kiln bya plnrality of mains 53. At intervals along the len h of the coolersection, nozzles ea are i provided. Said nozzles are inclined in thedirection of the upper end of the kiln. Further air nozzles 55' suppliedwith air from mains 53 are provided in the main kiln section intheconverging portion thereof, to supply air in the zone of the primarycombustion. Further nozzles 56 supplied main 53 are arrangedin the mainsection between the converging sec ion and the stack. The several airmains 53 communicate with a bustle pipe 57 that surroui'ids the kilnadjacent housing 10. A, plurality of air ports 58 converging toward theaxis of the kiln are arranged around he kiln with the axis of theiropenings in substan tially the same plane.

Communicating with the fuel chamber 19 are a plurality of fuel lines 59(see F Said lines communicate with a fuel bustle pipe 60 surrounding thethroat portion of the kiln. From said pipe the fuel is conveyed to thefuel ports 16 by conduits 61 and 62. I

Adjacent the end of the cooler section 3 a plurality of deliverysections and 64; are provided. These sections are annular chambers thatsurround the cooling section of the kiln as clearly shown in Fig... land 7. The cooling section is provided with openings 65 and 66, the oneopening communicating i "h the section 63 the other with ection 64:.clearly shown on the drawings, said openings are on diametricallyopposite sides of the kiln. Hinged covers 67 provided with chains 68 tolimit their opening movement are provided to close opening 65 and 66.Sections 63 and .6tare provided with A pipe 47 is external openings thatare diametrically op- The raw material is supplied to the kiln throughthe spout 12. Air under high pressure is supplied to the chamber fromthe pipe 51 as above described and fuel combined with air under lowpressure is supplied to the chamber 19 from pipe at as above described.The fuel is conveyed from the chamber 19 to the fuel port 16 by conduit59. At the same time, air is supplied under pressure to the nozzl s 54.55, 56 and 58. Combustion is initiated in the converging section of thekiln and rotation of the kiln is started. Inasmuch as the supply of fueland air is under control of the operator, the quantity and pressure maybe varied so hat substantially complete combustion of the fuel takesplace in the main section of the kiln.

The material moves along the kiln under the action of gravity and itsmovement endwise of the kiln will be retarded at the con-v vergingsection thereof. At this point, the combustion occurs at its maximumintensity and the material is burned to clinker. The products ofcombustion pass to the stack 11. The converging jets of air that enterthe kiln through the ports 58 substantially prevent the finely dividedsolid particles resulting from the burning of the material, fromentering the stack by causing said particles to move toward the Walls ofthe-kiln. Said particles are disposed on the raw material entering thekiln and pass out with the hot clinker.

The clinker enters the cooling section through the throat section inhighly heated condition and it gravitates along that section until itreaches the openings or 66 leading to the delivery sections 63 and 64.As it is moving along said section the air entering the nozzles 5dpasses over the hot clinker and is highly heated before entering thecombustion zone in the main section. The temperature of the clinker isthus reduced, while the temperature of entering air is raised. Furtherair is sucked into the cooler section through openings 29 in nozzle 28,said air entering the tube 26 through ports 72 provided in the end oftube 21. The quantity of air drawn into the kiln through these ports maybe varied under the control of the operator by suitably adjusting thepressure of the air that is admitted to the riln at various points alongthe length thereof, as above pointed out.

Substantially no air is admitted to the cooling section through thedischarge openings 65 and 66 because the gates 67 close said openingunder the action of gravity,.except when the opening is in itsdischarging position, when the clinker is permitted to drop into thedelivery section which itself at that time, is closed to the atmospheredue to the fact that. its discharge opening is then closed by gate 69under the action of gravity, said opening being arranged diametricallyopposite the opening in the kiln as above pointed out. The clinker isthus discharged without admitting substantial quantities of air duringsaid discharge.

The invention may be embodiedin other specific forms without departingfrom the spirit or essential characteristics, thereof. The presentembodiment is therefore to be considered in all respects as illustrativeand not restrictive, the scope of-the' invention being indicated by theappended claims rather thanv by the foregoing description, and allchanges which come within the meaning and range of equivalency of theclaims are therefore intended to be embraced therein;

What .we claim as our invention is: 1. A kilncomprising a tubular bodyarranged to rotate about an inclined axis composed of a main section anda cooling section connected by a throat section of reduced cllameter, ascompared to said sections, said main section adjacent said throat beingformed of gradually reduced internal diamcter, means tosu'pply fueltosaid main section adjacent its reduced diameter and means to supplyair to said body.

2. The combination defined in claim 1 in which means to supply the airto the body is arranged adjacent an end thereof whereby the airwill't'raverse said cooling section.

3. A kiln comprising atubular body arranged to rotate about an inclinedaxis to feed the contained material fromend to end thereof, means tosupply fuel to said kiln between its ends, means to supply air underpressure to said kiln at a plurality of points to support substantiallycomplete combustion of the fuel, some of said points being so disposedthat a substantial quantity of air is admitted adjacent one enclthereofand passesover the material heated to a high temperature at the zone ofadmission of the fuel. I

4.. The combination defined in claim 3 in which'the kiln body is ofgradually reduced internal diameter contiguous with the one or morepoints of admission of either fuel or air in order that the movement ofthe material in transit in the kiln is retarded in- 7 said zone.

6. A kiln comprising a closed body arranged to rotate about an inclinedaxis, fuel .and air chambers carried by said body, conduits conveyingthe fuel and air from said chambers to points along said body, astationary casing surrounding said body and mechanism rotating therewithto conduct the fuel and air to said chambers.

7. A kiln comprising a closed elongated cylindrical body arranged torotate on an inclined axis to cause the materlal to gravltate toward oneend of the kiln, a discharge opening in said end of the kiln, an annularchamber surrounding said opening and a discharge opening in saidchamber, said opening being arranged substantially diametricallyopposite said first named opening and covers to close said opening, saidcovers being arranged to be automatically closed by gravity in positionsother than their discharge positions.

8. A kiln of the rotary type including a plurality of diametricallyopposite discharge openings arranged adjacent one end of said kiln andout of alinement with each other, an annular chamber surrounding each ofsaid openings, each annular chamber being provided with an openingsubstantially in alinement with but diametrically opposite the kilnopening and covers for said kiln and chamber openings, said covers beingarranged to automatically gravitationally close said openings exceptwhen the kilns contents are discharged through said opening.

-9. That step in the method of burning cement in a rotary kilnsubstantially closed to the atmosphere and connected to a stack whichconsists in injecting fluid under pressure into the flow of the productsof combustion from said kiln in a direction transverse to said flowwhereby the flow into said stack of any solid particles becomesegregated from the gaseous products of combustion. 10. The method ofburning cement which consists in feeding the raw material into anenclosed elongated chamber, causing said material to move end-wise ofsaid chamber at varying rates of movement end-wise thereof, supplyingfuel at points where the ma terial moves relatively slow and supplyingair to the main section of the kiln under the control of an operator insuflicient quantities to insure substantially complete combustion insaid main section of the kiln.

11. A kiln comprising a cylindrical body substantially closed to theatmosphere at all points, arranged to rotate about an inclined axis inwhich the gradual reduction signatures.

ROBT. W. P. HORN. JACOB H. NISSLEY.

